<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>css案例</title>
    <style>
       .qaw{
           background-color: red;
           width: 100px;
           height: 100px;
       }
       .qaq{
        background-color: seagreen;
           width: 100px;
           height: 100px;
       }
    </style>
</head>
<body>
<div class="qaw"></div>
<div class="qaq"></div>
<div class="qaw"></div>
</body>
</html>